Various circuits for controlling electronic signals provided to audio speakers are known. In general, electric signals carry information to the speakers that then convert the information into sound. The electrical signals that carry the information may come in a variety of forms. For example, in certain devices, a pulse width modulated (“PWM”) signal may carry the audio data to the speaker for playback. By one approach, PWM signals carry information via a stream of pulses wherein variation in the width of the pulses conveys the information.
Electric amplifiers are provided in the circuits that convey information to a speaker. Generally, however, during power up of amplifiers connected to speakers, a spike in current or in the signal provided to the speaker can provide undesirable audio artifacts such as cracks or pops. To reduce such artifacts during power up, in the example of a PWM signal amplified system, the PWM signal may be modified to ramp up from a low level to a normal level at power up to reduce spiking of the signal.
Certain such systems for providing information to a speaker divide the signal that is used to provide information into two or more switched signals that are provided at the speaker to convey sound information. Although the signals may be processed through essentially identical circuit elements, inherent variations in the qualities of the elements may contribute to mismatch between the signals. Such mismatch errors can create unpleasant audio artifacts or otherwise degrade the quality of sound produced by the speaker.